High frequency power detector with dBm-linear characteristic and method of regulating the power of an electrical HF-oscillation

ABSTRACT

A high frequency power detector includes an input coupling arrangement that couples an electrical HF-oscillation into a basic circuit portion including at least a first diode and a circuit node. The power detector further includes a series circuit of a resistor and a second diode connected to the circuit node, as well as a voltage tapping arrangement for detecting or tapping the voltage drop across the second diode as an output signal. The voltage at the circuit node includes a DC component that depends on the power of the HF-oscillation. The output signal, i.e. the voltage drop of the second diode, has a linear voltage characteristic relative to the HF-power in dBm. A method of regulating the HF-power uses such a dBm-linear HF-power detector in a feedback loop for regulating the gain factor of an HF-amplifier.

PRIORITY CLAIM

[0001] This application is based on and claims the priority under 35U.S.C. §119 of German Patent Application 102 60 749.4, filed on Dec. 23,2002, the entire disclosure of which is incorporated herein byreference.

FIELD OF THE INVENTION

[0002] The invention relates to a high frequency (HF) power detectorwith a linear characteristic in dBm, including an input couplingarrangement for coupling-in an electrical HF-oscillation. The inventionfurther relates to a method of regulating the power of an electricalHF-oscillation using such a high frequency power detector.

BACKGROUND INFORMATION

[0003] A high frequency power detector and a power regulation method ofthe general type mentioned above, forming the field of this invention,is disclosed in U.S. Pat. No. 6,265,939 (Wan et al.).

[0004] This Patent discloses a power regulation method in which thepower is detected and used as an input signal for the power regulatingcircuit. In the scope of such a power regulation, it is desirable thatthe input signal varies linearly with the power detected in dBm.

[0005] As is generally known, the dimensionless power designation “dBm”is defined as the ten-fold common or base ten logarithm of the power inmW normalized to a reference power of 1 mW. In other words, “dBm” refersto decibels above 1 milliwatt, and defines a measure of power equal toten times the common logarithm of a ratio of a given power relative to0.001 watt. Thus, for example, a power of 20 mW can also be designatedor identified by the value 13 dBm. Thus, the term “dBm linear highfrequency power detector” is understood to mean a detector of which theoutput signal varies linearly with respect to the power of the highfrequency (HF) oscillation which is scaled or designated in dBm.

[0006] The high frequency power detector known from the U.S. Pat. No.6,265,939 comprises a rectifying diode (D1), which produces a DC voltagethat is dependent on the high frequency voltage coupled to therectifying diode through a capacitor. According to the Patent, the DCvoltage varies linearly with respect to the HF-power in dBm, at lowerpowers. However, at higher power levels, a non-linearity in thisrelationship arises, which must be compensated for. To achieve this, thePatent provides additional circuit stages which add additionalincremental loads the signal processing at various increased HF-powerlevels. In this regard, the additive incremental loads must bedimensioned so that the output signal of the HF-power detector varieslinearly with the HF-power output in dBm. The further circuit parts orstages comprise a network of a DC voltage source and several passiveelements, particularly six further diodes (D2 to D7), resistors (R2 toR12), and further capacitors.

[0007] The known circuit according to U.S. Pat. No. 6,265,939 isdisadvantageous because it requires an active voltage source and arelatively large number of passive components. For this reason, theknown circuit can only be realized with a relatively high productioneffort and expense. Moreover, the great number of necessary componentsrequires a relatively large surface area of the circuit, which isespecially disadvantageous in connection with an integration of such acircuit on a single chip.

[0008] High frequency power detectors based on diodes generally providean output voltage, which, depending on the magnitude of the coupled-inhigh frequency voltage, varies quadratically or linearly with respect tothe coupled-in high frequency voltage. Since the power of the electricalhigh frequency oscillation determines the effective value of thecoupled-in high frequency voltage, accordingly the output voltage of thehigh frequency power detector also varies quadratically or linearly whenit is plotted over the power in mW. Since a transformation of therepresentation of the power values in dBm rather than mW logarithmicallycompresses the power scale, a representation of the output voltage overthe power in dBm will exhibit an exponential characteristic. That istrue for both the original linear characteristic as well as the originalquadratic characteristic with respect to the power in mW.

[0009] In addition to the circuit construction according to the abovementioned U.S. Pat. No. 6,265,939, there are other known high frequencyvoltage-linear power detectors based on diodes, of which the outputvoltages must be linearized by at least one external stage. Such alinearizing stage may, for example, be embodied as a logarithmic (orlogarithm-producing) operational amplifier, which requires a negativevoltage, or as a microprocessor. Furthermore, a calibration process aswell as a temperature compensation must also be carried out forprocessing and compensating the output.

SUMMARY OF THE INVENTION

[0010] In view of the above, it is an object of the invention to providea dBm-linear high frequency power detector which does not require acalibration or an external temperature compensation, and which has asimplified circuit construction in comparison to the dBm-linear powerdetector according to U.S. Pat. No. 6,265,939, without active circuitcomponents and with a reduced number of passive circuit components.Another object of the invention is to provide a method using such asimple circuit for regulating the power of an electrical high frequencyoscillation. The invention further aims to avoid or overcome thedisadvantages of the prior art, and to achieve additional advantages, asapparent from the present specification. The attainment of these objectsis, however, not a limitation or required feature of the presentinvention.

[0011] The above objects have been achieved according to the inventionin a high frequency power detector including an input couplingarrangement adapted to couple an input electrical HF-oscillation into acircuit portion or sub-circuit that comprises at least a first diode anda circuit node, and that is adapted to produce at the node a signalincluding a DC component that is dependent on the power of the inputelectrical HF-oscillation. Especially according to the invention, thepower detector further comprises a series circuit coupled to the abovementioned node, whereby this series circuit includes a resistor and asecond diode, as well as a voltage tapping or detecting arrangement ordevice that taps or detects the voltage drop across the second diode asan output voltage signal.

[0012] The above objects have further been achieved according to theinvention in a method for regulating the power of an electricalHF-oscillation, using the power detector according to the invention in afeedback loop to monitor and regulate the output power.

[0013] In the circuit arrangement of the power detector according to theinvention, the voltage present at the above mentioned circuit nodecorresponds to the total voltage drop across the series circuit of theresistor and the second diode. The voltage at the node, i.e. the voltagedrop across the series circuit, corresponds or is proportional to theoutput voltage of a normal high frequency power detector. As will bedescribed in further detail below, the partial voltage drop across theresistor in this additional series circuit depends exponentially on thevalue of the partial voltage drop across the second diode. As a result,the partial voltage drop across the second diode takes on valuesexhibiting a linear relationship or characteristic relative to the powerplotted in dBm.

[0014] Thus, when the output voltage signal is tapped across the seconddiode, i.e. to correspond to the partial voltage drop across the seconddiode, the desired dBm-linear output voltage can be achieved without anyactive circuit components and with only two passive circuit components,namely the resistor and the second diode of the added series circuit. Anequalization, compensation, or correction of the output characteristicthrough an additional output stage or circuit is thus not necessary.Furthermore, the addition of the simple series circuit according to theinvention can easily be integrated into a single integrated circuitwithout any problems. The small surface area or space required by thepresent simple circuit represents a further advantage in the case of theintegration of this circuit.

[0015] According to a preferred feature of the invention, the firstdiode and the second diode are of the same type or structure. In thismanner, type-specific influences of the first diode on the outputvoltage of the high frequency power detector will be compensated bysimilar such influences of the second diode. More particularly, it isfurther preferred that both diodes are Schottky diodes. Due to their lowdepletion layer or junction capacitance, Schottky diodes are especiallywell suited for processing high frequency signals, as in the presentapplication.

[0016] Another preferred feature of the invention is that both diodesare thermally coupled to each other, for example through any suitablethermally conductive substrate or the like. Such a thermal coupling ofthe diodes ensures that both diodes will always operate at the sametemperature level. For this reason, temperature induced variations ofthe output signals of the first diode will be compensated by the seconddiode.

[0017] Still a further preferred feature of the invention is that bothdiodes are components of a single integrated circuit. An integration ofboth diodes on a single chip makes it possible to accommodate theadditional series circuit easily while saving surface area of thecircuit, and while simultaneously benefitting the thermal coupling ofthe two diodes, which improves the compensation of temperatureinfluences as mentioned above.

[0018] In another preferred embodiment of the invention, the inputcoupling arrangement for coupling the input electrical HF-oscillationinto the circuit comprises at least a first capacitor. Particularly, theuse of one or more capacitors achieves a low-loss and signal-truecoupling of the high frequency signal into the detector circuit.However, the invention is not limited to circuit arrangements usingcapacitive coupling of the input signal, but rather other forms of inputcoupling arrangements, for example using inductive coupling, can beprovided instead or in combination according to the invention.

[0019] It is further preferred that the first circuit portion orsub-circuit comprises a peak value rectifier. Such peak value rectifiersare conventionally known in various different arrangements,configurations and embodiments, and any of such known rectifiers can beused. Such peak value rectifiers provide a voltage that is linearlydependent on the high frequency input voltage. Therefore, such arectifier can be easily dBm-linearized according to the presentinvention without much circuit effort or expense, through combinationwith the inventive series circuit of a second diode and an additionalresistor. Further preferably, the peak value rectifier comprises thefirst diode as well as a further (third) diode. The further diode, thefirst capacitor, and the high frequency voltage source form a first meshor loop of the circuit, while the further diode, the first diode, and asmoothing capacitor form a second mesh or loop of the circuit (in themanner of a so-called Villard circuit). Such a Villard circuitrepresents a simple example of a suitable peak value rectifier, which,in combination with the inventive additional series circuit, willprovide the desired dBm-linear characteristic of the output voltage.

[0020] Further preferably according to the invention, the series circuitof the resistor and the second diode, together with the second capacitor(i.e. the smoothing capacitor), forms a third mesh or loop of thecircuit. In this case, as mentioned above, the second capacitor acts asa smoothing capacitor, which improves the DC quality or character of thevoltage that is applied to the series circuit. This in turn improves thequality of the dBm-linear signal detection.

[0021] Further advantages and features of the invention are apparentfrom the present specification as well as the accompanying drawings. Itshould be understood that the various features and elements disclosedherein are not only useable in the respective particular disclosedcombination, but rather the invention also covers all other combinationsas well as individual provision of any one or more of the respectiveinventive features.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order that the invention may be clearly understood, it willnow be described in connection with example embodiments thereof, withreference to the accompanying drawings, wherein:

[0023]FIG. 1 is a basic schematic circuit diagram of a high frequencypower detector according to the invention;

[0024]FIG. 2 is a graph of the calculated curve or progression of thevoltage U relative to the power P of a high frequency signal scaled indBm, whereby the voltage U is the voltage on an internal circuit node ofthe inventive detector circuit, or could be the output voltage of aconventional detector circuit;

[0025]FIG. 3 is a graph of the calculated curve or progression of theoutput voltage U_D of the high frequency power detector according to theinvention, relative to the power P of a high frequency input signal indBm;

[0026]FIG. 4 is a graph of the actual measured voltage V of the internalcircuit node voltage U and the output voltage U_D of an exampleembodiment of the inventive detector circuit; and

[0027]FIG. 5 is a highly schematic block circuit diagram of a regulationcircuit for regulating a high frequency power using a dBm-linear powerdetector according to the invention.

DETAILED DESCRIPTION OF A PREFERRED EXAMPLE EMBODIMENT AND OF THE BESTMODE OF THE INVENTION

[0028] As schematically shown in FIG. 1, an overall high frequency (HF)circuit 10 includes an HF-voltage source 12 and an HF-power detector 14according to the invention for detecting the HF-power output of theHF-voltage source 12. The HF-voltage source 12 may, for example, berealized as a collector oscillating circuit of a transistor. Theinventive HF-power detector 14 comprises an input coupling arrangement16, a peak value rectifier 18, a smoothing capacitor 24, an internalcircuit node 26, a series circuit 28 forming an output stage, and avoltage tapping or detecting arrangement or means 34 such as a voltmeteror simply output terminals or taps. While it is not shown in FIG. 1, thecircuit arrangement may be grounded or connected to a reference voltageat any suitable location. For example, the common conductor shown at thebottom of FIG. 1, which is connected to the negative side of the voltagesource 12, could be grounded.

[0029] The input coupling arrangement 16, which comprises a firstcapacitor 17 in the present example embodiment, couples the HF-signalprovided by the HF-voltage source 12 into a first circuit portion orsub-circuit (including the peak value rectifier 18 and the smoothingcapacitor 24) of the HF-power detector 14. The peak value rectifier 18comprises a first diode 20 and a further (third) diode 22. Therectifying effect of the peak value rectifier 18 is based on thenon-linear course or progression of the diode characteristics of thediodes 20 and 22, as is generally known. Due to this exponential courseor progression of the current-voltage characteristics of these diodes,the positive and negative half-waves of the input HF-signal are deformedin such a manner so that the output signal of the peak value rectifier18 provided at the internal circuit node 26 comprises a DC component.

[0030] With sufficiently large input AC voltages, the output voltage ofthe peak value rectifier 18 will behave proportionally to the peak valueof the input AC voltage. The smoothing capacitor 24 serves to smooth thedeformed or reformed rectified AC voltage provided by the peak valuerectifier 18. Thus, a smoothed AC signal comprising a DC component isprovided at the internal circuit node 26.

[0031] The above described portion of the circuit arrangement 10represents a particular rectifier circuit that is generally known as aVillard circuit. The various identified circuit components are connectedtogether in the embodiment according to FIG. 1 in such a manner so thatthe HF-voltage source 12, the input coupling arrangement 16, and thefurther (third) diode 22 form a first mesh or loop 36 of the overallHF-circuit 10, while the further (third) diode 22, the first diode 20,and the smoothing capacitor 24 form a second mesh or loop 38 of thecircuit 10. This rectifier circuit, which is known as such, provides atthe internal circuit node 26, a signal with a DC component that isquadratically or linearly dependent on the input HF-voltage. When usinga peak value rectifier, for example, the linear dependence prevails.

[0032] Further according to the invention, the rectifier circuit thatprovides the above described signal at the internal circuit node 26, isfurther combined with an additional series circuit 28 of a resistor 32and a second diode 30. Thereby, in the illustrated example embodiment ofFIG. 1, the resistor 32 and the second diode 30 of the series circuit28, together with the smoothing capacitor 24, form a third mesh or loop40 of the overall circuit 10.

[0033] In the above described circuit, the voltage prevailing at theinternal circuit node 26 drives a current I through the series circuit28 of the resistor 32 and the second diode 30. The resistor 32 and thesecond diode 30 form a voltage divider, so that the sum of the voltagedrop U_D across the second diode 30 and the voltage drop U_R across theresistor 32 give the voltage U prevailing at the node 26. Furthermore,the voltage drop U_R across the resistor 32 is given by the product ofthe resistance and the current flowing therethrough, namely U_R=R·I.This current I that determines the resistor's voltage drop U_R, alsoflows through the second diode 30 and there causes the diode's voltagedrop U_D. In view of the diode characteristic, the current I isproportional to the exponential function exp(U_D) of the voltage drop onthe second diode 30. Since this same current also flows through theresistor 32, the current flowing through the resistor 32 and thus thevoltage drop U_R on the resistor 32 will also be exponentially dependenton the diode voltage drop U_D.

[0034] Thus, the total voltage drop in the series circuit 28 is formedby the sum of a linear component, namely the voltage drop U_D on thesecond diode 30, and a term that is exponentially dependent on thisvoltage drop U_D, namely the voltage U_R on the resistor 32. Since theexponentially dependent term dominates the value of the above mentionedsum, the total voltage drop U on the series circuit 28 is essentiallyexponentially dependent on the diode voltage drop U_D. In other words, Uis approximately proportional to exp(U_D), or the voltage at theinternal circuit node 26 is approximately exponentially proportional tothe voltage drop across the second diode 30.

[0035] Therefore, the inverse is also true, namely the voltage drop U_Don the second diode 30 is (approximately) logarithmically dependent onthe voltage U prevailing at the internal circuit node 26. In otherwords, U_D is (approximately) proportional to Log U and thus is alsoproportional to the logarithm of the power of the HF-signal normalizedto a reference value. This further means that the voltage drop U_D onthe second diode 30 is approximately proportional to the HF-power givenin dBm, within the scope of the above mentioned approximation, i.e. ifthe exponentially dependent term dominates the above mentioned sum ofthe two voltage drops on the resistor 32 and the second diode 30. Thevalidity of this approximation can readily be ensured by appropriateselection of the circuit elements.

[0036]FIG. 2 shows the calculated exponential course or progression ofthe voltage U relative to the HF-power P plotted in dBm. Thischaracteristic progression of the voltage U prevails at the internalnode 26 of the HF-circuit 10. The exponential nature of the voltagecharacteristic is apparent. If the two circuit meshes or loops 36 or 38including the rectifier 18 and the smoothing capacitor 24 would be useddirectly as a power detector, with the output signal provided at thenode 26, it is apparent that the output would have an exponentialdependence on the HF-voltage and correspondingly the HF-power.

[0037] In comparison to FIG. 2, FIG. 3 shows a graph of theapproximately linear progression of the calculated voltage drop U_D thatis tapped or detected across the second diode 30, in the series circuit28 of the resistor 32 and the second diode 30 that has been added to theoverall circuit 10 according to the invention. In the illustratedexample of FIG. 1, this voltage drop U_D is detected or tapped as theoutput signal across the second diode 30, by any suitable voltagetapping arrangement or means, such as a voltmeter 34.

[0038] The respective voltage curves illustrated in FIGS. 2 and 3 wereeach calculated through the use of a simulation model of the circuitaccording to the invention, for an HF-signal frequency of 1 GHz. Thecalculated results of FIGS. 2 and 3 discussed above were furtherqualitatively confirmed through actual measurements on real circuits.These actual measured results are illustrated in FIG. 4.

[0039] In FIG. 4, the voltage curve 42 corresponds to the approximatelylinear progression of the output voltage U_D across the second diode 30.On the other hand, the voltage curve 44 represents the voltage Uprevailing at the internal circuit note 26, and generally corresponds tothe exponential progression of the voltage as shown by the calculatedcharacteristic in FIG. 2.

[0040] It can be seen that the actual measured voltage curve 42 is notexactly linear. This may arise because the measurements for thequalitative testing were carried out on a circuit that was coupled to anormal HF-detector circuit. Thereby, diodes 1N4148 and 1N4004, which arenot Schottky diodes, were used. Instead, when using suitable matchedSchottky diodes, which are integrated on a single chip with the rest ofthe HF-detector circuit, it is expected that a further improvedcorrespondence of the actual measured voltage curves with the calculatedcurves according to FIGS. 2 and 3 would be achieved.

[0041] Nonetheless, the actual measured U_D curve 42 shown in FIG. 4already exhibits an approximately linear characteristic in comparison tothe substantially more sharply curved and essentially exponentialcharacteristic of the U curve 44. Namely, while the incline slope of thecurve 42 is initially greater at lower power values, it then becomessmaller at higher power values (in comparison to the curve 44). Also,the slope of the curve 42 clearly fluctuates about an average value,while on the other hand the slope of the curve 44 continuously increasesin a generally exponential manner. Such a characteristic of the curve 42having a slope fluctuating about an average slope value can beunderstood as defining a “substantially linear” characteristic.

[0042] While the U curve 44 in the present context represents thevoltage prevailing at the internal circuit node 26, it should further beunderstood that this voltage characteristic corresponds to the expectedexponential progression or characteristic of the output voltage of aconventional HF-detector circuit using only a peak value rectifiercircuit without the inventive additional series circuit 28, with respectto the power of the coupled-in HF-signal plotted in dBm, i.e.logarithmically.

[0043]FIG. 5 illustrates, in a strongly schematic manner, a regulationcircuit for regulating a high frequency power while using a dBm-linearpower detector 14 according to the invention. An HF-signal provided byan HF-signal transducer or generator 46 is provided to and amplified inan HF-amplifier 47 that has a controllable amplification or gain factor.The resulting amplified signal is, for example, radiated from an antenna48. In order to regulate the transmitting power, a portion of theHF-signal is coupled out of the circuit path downstream from theHF-amplifier 47 and into the HF-power detector 14. This HF-powerdetector 14 is the inventive dBm-linear HF-power detector, which may beembodied according to FIG. 1 as described above.

[0044] The output signal of the HF-power detector 14, i.e. the voltagedrop U_D over the second diode 30 of the series circuit 28 of FIG. 1, isprovided as a measured actual value to a regulator 50. A nominal ordesired value indicating the desired HF-power level is further providedto the regulator 50 from a nominal or desired value transducer or input52, for example a memory cell of a regulation electronics arrangement.Based on the actual measured value and the desired or nominal value ofthe HF-power, for example by comparing these two values using acomparator, the regulator 50 forms an adjustment value or regulationsignal, which is transmitted over a signal path 54 to the gain controlinput of the HF-amplifier 47, whereby the amplification or gain factoris regulated. The regulation method according to the invention thusinvolves the sequence of steps as just described for the operation ofthe regulation circuit according to FIG. 5.

[0045] In this context, the invention is based on the use of adBm-linear HF-power detector 14 in the illustrated regulation circuit47, 14, 50. However, the invention is not limited to the use of theparticular HF-detector 14 using a Villard circuit as shown and describedabove in detail in connection with FIG. 1. Instead, the invention allowsfor the use of any desired HF-power detector based on diodes, combinedwith an added series circuit 28 of a resistor 32 and a second diode 30,whereby the voltage drop on the second diode 30 is detected or tapped asthe dBm-linear output value or measure for the HF-power. Examples ofother rectifier circuits based on diodes that can be used as the basicstarting-point sub-circuit of the present inventive detector circuitinclude series rectifiers and full wave rectifiers embodied as centertap circuits or bridge circuits, with any conventionally known circuitarrangements. Such rectifiers are generally known to a person ofordinary skill in the art, and thus do not need to be described hereinin detail. For example suitable rectifier circuits of this type aredisclosed in the reference book by Meinke Gundlach, “Taschenbuch fuerHochfrequenztechnikt” (Pocketbook for High Frequency Technology), 5thEdition, Vol. 1, ISBN 3-540-54714-2, page G32. Moreover, in addition toor instead of capacitive input coupling elements 16, 17, the circuitarrangement according to the invention could use inductive couplingelements for coupling an HF-power into the HF-power detector.

[0046] Although the invention has been described with reference tospecific example embodiments, it will be appreciated that it is intendedto cover all modifications and equivalents within the scope of theappended claims. It should also be understood that the presentdisclosure includes all possible combinations of any individual featuresrecited in any of the appended claims.

What is claimed is:
 1. A high frequency power detector circuitarrangement comprising: a sub-circuit comprising a first diode and acircuit node; a coupling arrangement that is connected to saidsub-circuit and that is adapted to couple into said sub-circuit anelectrical high frequency oscillation applied to a first input terminalof said coupling arrangement; a series circuit that is connected to saidcircuit node and that comprises a resistor and a second diode connectedin series with one another; and a voltage tapping arrangement connectedto said second diode and adapted to tap or detect a voltage drop acrosssaid second diode.
 2. The high frequency power detector circuitarrangement according to claim 1, wherein said series circuit consistsof said resistor and said second diode and one or more conductor pathsconnecting said resistor and said second diode in series with oneanother, and wherein said resistor and said second diode form a voltagedivider between said circuit node and a downstream side of said seconddiode.
 3. The high frequency power detector circuit arrangementaccording to claim 2, wherein said resistor is connected to andinterposed between said circuit node and an upstream side of said seconddiode.
 4. The high frequency power detector circuit arrangementaccording to claim 1, further comprising a common reference conductorand a second input terminal connected to said common referenceconductor, wherein said sub-circuit and said series circuit are eachfurther connected to said common reference conductor, and wherein saidvoltage tapping arrangement includes a first voltage output leadconnected to a point that is connected and interposed between saidresistor and said second diode, and a second voltage output leadconnected to said common reference conductor.
 5. The high frequencypower detector circuit arrangement according to claim 4, furthercomprising a high frequency input voltage source connected to said firstinput terminal and said second input terminal.
 6. The high frequencypower detector circuit arrangement according to claim 1, wherein saidsub-circuit is adapted to produce at said circuit node a signal thatincludes a DC signal component that is dependent on a power of theelectrical high frequency oscillation.
 7. The high frequency powerdetector circuit arrangement according to claim 1, wherein saidsub-circuit comprises a peak value rectifier circuit.
 8. The highfrequency power detector circuit arrangement according to claim 7,wherein said peak value rectifier circuit comprises the first diode anda further third diode, wherein said circuit arrangement furthercomprises a high frequency input voltage source connected to said firstinput terminal and to said third diode, and wherein said third diode,said coupling arrangement and said input voltage source together form afirst mesh of said circuit arrangement.
 9. The high frequency powerdetector circuit arrangement according to claim 8, wherein saidsub-circuit further comprises a smoothing capacitor, wherein said thirddiode, said first diode and said smoothing capacitor together form asecond mesh of said circuit arrangement with said circuit node betweensaid first diode and said smoothing capacitor.
 10. The high frequencypower detector circuit arrangement according to claim 9, wherein saidsmoothing capacitor, said resistor and said second diode together form athird mesh of said circuit arrangement.
 11. The high frequency powerdetector circuit arrangement according to claim 1, wherein said voltagetapping arrangement is adapted to provide an output signal indicative ofsaid voltage drop across said second diode, which depends on and isindicative of a power of the electrical high frequency oscillationapplied to said first input terminal of said coupling arrangement. 12.The high frequency power detector circuit arrangement according to claim11, adapted so that said output signal varies substantially linearlywith respect to the power of the electrical high frequency oscillationrepresented in dBm.
 13. The high frequency power detector circuitarrangement according to claim 1, wherein said first and second diodesare both of the same diode type.
 14. The high frequency power detectorcircuit arrangement according to claim 1, wherein said first and seconddiodes are both respective Schottky diodes.
 15. The high frequency powerdetector circuit arrangement according to claim 1, wherein said firstand second diodes are thermally coupled to each other.
 16. The highfrequency power detector circuit arrangement according to claim 1,wherein said circuit arrangement comprises an integrated circuit, andsaid first and second diodes are both integrated into said integratedcircuit.
 17. The high frequency power detector circuit arrangementaccording to claim 1, wherein said coupling arrangement comprises aninput coupling capacitor.
 18. The high frequency power detector circuitarrangement according to claim 1, expressly excluding active elementsand including only passive elements.
 19. The high frequency powerdetector circuit arrangement according to claim 1, further comprising: ahigh frequency variable gain amplifier with an output connected to saidfirst input terminal and adapted to apply the electrical high frequencyoscillation thereto; a high frequency signal generator connected to aninput of said amplifier; a desired value transducer; a regulator havinga desired value input connected to said desired value transducer, andhaving an actual measured value input connected to said voltage tappingarrangement, and having a control signal output connected to a gaincontrol input of said amplifier.
 20. A method of regulating the power ofan electrical high frequency oscillation using the circuit arrangementaccording to claim 1, comprising the steps: a) generating said highfrequency oscillation and applying said high frequency oscillation tosaid first input terminal; b) detecting said voltage drop across saidsecond diode; and c) regulating said power responsive to and dependenton said voltage drop.
 21. A high frequency power detector circuitarrangement comprising: input coupling means for coupling an electricalhigh frequency oscillation into said circuit arrangement; a sub-circuitincluding rectifier means for providing, at a node, a signal including aDC component dependent on the power of the high frequency oscillation; aseries circuit connected to said node and including a resistor and adiode; and first and second output voltage terminals respectivelyconnected to opposite sides of said diode and adapted to provide avoltage output signal between said terminals corresponding to a voltagedrop across said diode.
 22. A high frequency power detector circuitarrangement comprising: a first input terminal and a second inputterminal; an input coupling arrangement comprising at least one of acoupling capacitor and a coupling inductor connected to said first inputterminal; a rectifier arrangement connected to said input couplingarrangement, said second input terminal, and a circuit node; a seriescircuit including a resistor and a diode connected in series betweensaid circuit node and said second input terminal; and first and secondoutput terminals respectively connected to opposite sides of said diode.23. The high frequency power detector circuit arrangement according toclaim 22, further comprising a smoothing capacitor connected parallel tosaid series circuit between said circuit node and said second inputterminal.
 24. The high frequency power detector circuit arrangementaccording to claim 22, wherein said resistor is connected to saidcircuit node and said diode is connected in a forward feed directionfrom said resistor to said second input terminal.
 25. The high frequencypower detector circuit arrangement according to claim 22, wherein saidrectifier arrangement comprises a first rectifier diode connected in aforward feed direction from said input coupling arrangement to saidcircuit node, and a further rectifier diode connected in a forward feeddirection from said second input terminal to said input couplingarrangement and said first rectifier diode.